Insulation cutting tool



Dec.y 7, 1948. w. s. LINDSAY INSULATION CUTTING TOOL Filed Dec.

BY MQ M Patented Dec. 7, 1948 UNITED l STATES PATENT OFFICE f "i l 2,455,591 l A VINSULATION CUTTING TOOL William S. Lindsay, Harriman, Tenn., assignor,

by mesne assignments, to the United States of `America as represented by the United States `Atomic Energy Commission Application December 4, 194i, senat No. 566,584

This invention relates to devices for cutting 1the finsulation on insulated cables for purposes of stripping or removing the insulation fromthe cable. Electrical cables may have only a single layer of insulation or there may be two or more `layers of insulation with a layer of metal between the layers of insulation, that is, there may be an electrically conductive sleeve or covering `around the first layer of insulation which forms ja conductor for electrical current at a different voltage; It may be desired to strip the cableyall `of the way downto the core or it may be` desired -onlytostrip it down toa certain depth and in 2 claims. (o1. .ac- 95) insulation consisting of a cylindrical element of l a size to fit snugly over. the cable and having a knife edge associated therewith so arranged that .as the member is rotated onthe cable a circum- `.ierential `cut in the insulation of any desired fdepth` can be made.

Another object of the invention is to provide a device as set forth in the preceding object in combination with a clamping member adapted to be clamped to the cable so as to serve :as a guide for the rotational movement of the cutting tool as it is rotated for making the cut in the insulation.

Further objects of my invention and numerous of its advantages will become apparent from the following detailed description and annexed drawing wherein Fig. 1 is a plan View of the cutting tool of my invention showing it in place on the cable with the clamping ring or guide also in place on the cable.

Fig. 2 is a view partially in section of the cutting tool of Fig. 1.

Fig. 3 is a view of the clamping device.

Fig. 4 is a sectional end view of the cutting tool of Figs. 1 and 2. 1

Fig. 5 is a detailed view of the clamping ring or guide member in place on the cable.

Referring to the figures, numeral I0 designates the main element of the device and it consists simply of a length of cylinder of a size such that it will snugly `t over an insulated cable from which it is desired to strip the insulation. The cylinder member IIJ may be several inches long in the direction of its axis so as to provide a considerablelbearing" surface between the inside of the memberfl and the exteriorsurface ofthe cable insulation. The cutting tool is shown in place on the cablejin Fig. "`1`, the cable being designatedby the numeral Il and the cable also beingshown in Fig. 4 and in Fig."5 "with the guide ring or@ member l2 of my invention l clamped around` thecable.` "Ifhe cable is shown as com- `prising acentral conductor or core "l5`ha'ving a rst layer of insulation I6` thereon and a second layer of insulation, l1' withfa metallic covering `or sleeve l8` laroundfthe` `first layer of insulation, that is,V interposed between the two layerslof insulationf" Surroundingthe second layer of insulation" Il" is a sleeve or sheath made of interlaced or interwoven copper braid material which in practice is used as a grounded sheath, thatis, it distributes any staticcharge that there may be onithe outside `of the cable and the sheathis connected to ground `for carrying off this charge.

`It isl to be understood, of course, that the device ofrnyinvention can be used for stripping insu1ation `from cables of other types than the one J'ust described.

The cylindrical member lllhas attached there- `to a handle 20 by means of rivets as shown, the fhandle 20 extending tangentially from the cylin- Numeral 2l indicates a slot drical member lll.

in the side wall-of the member l0 which is aligned with thehandle" 20. Upstanding from the handle 2D are a pair of `brackets 23fand 24 which are riveted to the handle and which have slots in them aligned with each other and with the slot 2l. Numeral 25 indicates a knife or a member having a knife edge which extends through the slots in the brackets 23 and 24 and into the slot 2| as may be seen on Fig. 4. The knife edge lies in a plane perpendicular to the longitudinal axis of the cylindrical member I0, the inner end of the knife edge member 25 being rounded oif as shown in Fig. 4 to conform to the curvature of the member I0.

In operation the member I0 is slipped on the cable to the point where it is desired to make a cut in the insulation for stripping it off, with the knife edge member 25 retracted, that is, withdrawn from the slot 2l. The knife member 25 is then inserted into the slot 2l, cutting into the insulation as it does so to an extent depending upon the `depth of circumferential cut desired in the insulation. After the knife member 25 has been inserted, the handle 2U is grasped with the operator grasping the knife edge member 25 at the same time as he grasps the handle 20 to hold the knife edge member in position and the member I0 is then rotated through one complete revolution. This makes a uniform circumferential cut in the insulation of a depth depending upon the extent to Which the knife edge member 25 was inserted. After the cut has been made 'the knife edge member 25 can, of course, be easily retractedi and thermember Ill carixbel slipped along the cable: away from 'the cut and' the insulation can then be easily stripped off down to the depth of the cut. If the cut is not quite deep enough the tool can quickly be slipped back into position and the knife edge member 25 agairr"insertedlv and l another cut made similarly so. asto cut. into the.

insulation to the desired extentandfthiszcan easily be done in the manner described Without damaging the underlying metal sleeve I8 or the core .Ii. The operation is extremely easy to perform and it requires practically no skill on the'part of the operator.

In order to positively insure that the member I0? does not, slipor slide longitudinally along the cable during the operation, and to relieve the operator of having to hold .it against such sliding or slipping, I provide: a guiding device. I2 which consistsof a clamp comprising of -tvvo half round elements 29 and 30- as sholvvn or-ilig.` 5. which are hinged together by Ymeans of a. hinge 3| and which have matching. flanges 324 and 33 which can be securely clamped together by a Wing nut 34. The device I2 is of such size that When it is clamped on the cable and the Wing nut 34 tightened up. the device: is held securely in position` on the cable. The cutting tool is then slid along, the. cableuntil its .edge bears against the guide ring. or member I2` and as the cutting tool is rotated it is accurately guidedin its rotational movement by themember I2. vThe member I2 is, of course, clamped on the cable-at a point adjacent. Whereit is-desired that the out` be made in in its results. By means of the tool and the guide device I2, cylindrical cuts can be made to any desired depth and at any point along the cable either for stripping off insulation at the end of a cable or between two spaced points along the cable.

The foregoingv disclosure is representative of a preferred. form of my invention and it is intended that the disclosure be interpreted in an illustrative rather than a limiting sense and that the scope of the invention be determined only in accordance with the claims appended hereto.

I claim:

' L A cable insulation cutting device of the character described comprising an elongated cylindrical sleeve for disposition about the insulation of .a cable, a slot extending transversely across the body of said sleeve, a handle mounted on said sleeve adjacent one end for pivotal movement about said mounting, and a cutter on said `handle for movement into said slot radially of the'sleeve for cutting the insulation of the'cable as the sleeve is rotated thereon. l

2'. A cable insulation. cutting device of the character described comprising an elongated cylindrical sleeve for disposition about the insulation of a cable, a slot extending transversely across thel body of said sleeve, a `handle mounted on said sleeve adjacent one. end, for pivotal movement about said mounting,l a cutter on. said handle for movement into said slotradiallycf the sleeve for cutting theY insulation'of the cable as the sleeve isrotated thereon, and a split: ex'- pansible guide for clamping engagementwithzthe cable toprovide a continuous circumferential guiding surface for limiting axial movement of the sleeve.

WILLIAM S. LINDSAY.

REFERENCES' CITED' The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name. Date 18,918 Lloyd Dec. 22, 1857 81,402 Peace Aug. 25, 1868 1,279,022 Scott Sept. 17,v 1918 2,317,944 Schaefer Apr.V 27, 1943 

